<?php 
$phone="608-473-759";

//$phone = preg_replace("/[^0-9\(\)]/","",$phone); 
if( !preg_match("/^([1]-)?[0-9]{3}-[0-9]{3}-[0-9]{4}$/i", $phone) ) {
//if( !preg_match("/[^0-9]{3}-[0-9]{3}-[0-9]{3}/", $phone) ) {
    echo 'Please enter a valid phone number';
	return false;
 }
else echo 'Numer telefonu jest dobry';
    
?>